Department of Psychology, University of Milano - Bicocca, piazza dell'Ateneo Nuovo, 1, 20126 Milan, Italy.
Noser Engineering AG, Root Längenbold, Switzerland.
Neuropsychologia. 2014 Jan;53:178-86. doi: 10.1016/j.neuropsychologia.2013.11.017. Epub 2013 Dec 1.
The way in which humans represent their own bodies is critical in guiding their interactions with the environment. To achieve successful body-space interactions, the body representation is strictly connected with that of the space immediately surrounding it through efficient visuo-tactile crossmodal integration. Such a body-space integrated representation is not fixed, but can be dynamically modulated by the use of external tools. Our study aims to explore the effect of using a complex tool, namely a functional prosthesis, on crossmodal visuo-tactile spatial interactions in healthy participants. By using the crossmodal visuo-tactile congruency paradigm, we found that prolonged training with a mechanical hand capable of distal hand movements and providing sensory feedback induces a pattern of interference, which is not observed after a brief training, between visual stimuli close to the prosthesis and touches on the body. These results suggest that after extensive, but not short, training the functional prosthesis acquires a visuo-tactile crossmodal representation akin to real limbs. This finding adds to previous evidence for the embodiment of functional prostheses in amputees, and shows that their use may also improve the crossmodal combination of somatosensory feedback delivered by the prosthesis with visual stimuli in the space around it, thus effectively augmenting the patients' visuomotor abilities.
人类对自身身体的呈现方式对于指导其与环境的相互作用至关重要。为了实现成功的身体-空间相互作用，身体的呈现方式通过有效的视触模态整合与周围空间的呈现方式紧密相连。这种身体-空间的综合呈现方式不是固定的，而是可以通过外部工具的使用进行动态调节。我们的研究旨在探索使用复杂工具（即功能性假肢）对健康参与者的视触模态空间相互作用的影响。通过使用视触模态一致性范式，我们发现，使用能够进行远端手部运动并提供感觉反馈的机械手进行长时间训练会引起一种干扰模式，而在短暂训练后则不会观察到这种模式，这种干扰模式表现在与假肢附近的视觉刺激和身体上的触觉之间。这些结果表明，经过广泛但不是短暂的训练后，功能性假肢获得了类似于真实肢体的视触模态表示。这一发现增加了先前关于功能性假肢在截肢者中体现的证据，并表明它们的使用还可以改善假肢提供的感觉反馈与周围空间中的视觉刺激的跨模态组合，从而有效增强患者的视觉运动能力。
